TCCA is the basic material for a large class of household and industrial products used for treating the water of swimming pools, cooling towers, toilet bowls, detergents, paper industry, and the like. It is sold as tablets of various forms and sizes or as granulated material or powder.
TCCA is a powerful oxidant and as such its transportation and shipping is regulated by rules, varying from country to country, regarding packaging requirements. The packages should bear a warning label showing the oxidant characteristics and should be constructed so that any contact of their contents with organic or oxidizable matter is avoided. For the USA these rules are elaborated by the Department of Transportation (DOT). The packaging requirements are described in the Code of Federal Regulations (CFR), Title 49, Transportation, Parts 100-185 (Revised as of Oct. 1, 2000), §173.127(1), “Class 5, Division 5-1—Definition and Assignment of Packing Groups”. The classification of packages is done according to the results of a testing procedure described by the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, Section 34, Test O.1 “Test for Oxidizing Solids” (hereinafter, “the UN test”). To the applicant's best knowledge, prior art TCCA formulations that comply with these stringent requirements and do not require the “oxidant” labeling are not available on the market and have not been disclosed. Some formulations have been disclosed that were claimed to pass the old DOT test (hereinafter “the DOT test”) for ignitability. Said test, described in Appendix F (now abandoned) to Part 173 made a comparison between the burning time of standard mixtures that used saw dust as combustible matter and a mixture of potassium bromate and potassium perchlorate as reference oxidizing material and 4:1 and 1:1 mixtures of the oxidizer to be tested with the same saw dust. Saw dust is not a well defined combustible material and contains lignin, a phenolic constituent of the wood, whose combustibility is low. This allows longer burning times of the standards and more possibility of the tested material to pass the test. However, the DOT test was abandoned and replaced with the UN test, so that the fact that a formulation passes the DOT test is not significant. The main difference between the UN test and the DOT test is that the first uses as combustible material dry, micronized cellulose fibers, well characterized by the particle size and moisture content, and uses potassium bromate alone as reference oxidant. In some cases, compositions that would not pass said test are allowed to be marketed without a warning labeling because they are limited to small packages (less than 1 kg., Package Group III).
U.S. Pat. No. 6,068,791 describes formulations containing 72-72.1% TCCA, 2.9-3.2% glycoluril, 18% Alum, 6.8% Borax and 0.1% Boric acid that are stated (but not claimed) to be able to pass the DOT test for comburancy. These mixtures contain relatively low levels of TCCA, which are not as efficient for water treatment or cleaning applications.
U.S. Pat. Nos. 5,478,482, 5,670,059 and 5,514,287 describe mixtures of 60% sodium-dichloro-s-triazinetrione (Na dichloro-isocyanurate) with 20-30% Na persulfate, 10% Na tetraborate, 0-10% aluminum sulfate and 0-20% oxone, that apparently are non-comburant by the DOT test (though this again is stated but not claimed). These compositions contain ca 36% available chlorine only, so that it could be expected that, at this level, the oxidative properties would not be significant.
It is clear, therefore, that no TCCA composition is known in the art that has high biocidal properties, and yet is non-comburant according to the UN test, is less dangerous for transport and storage than the known compositions, and does not require special labeling. It is the purpose of this invention to provide such a composition.
It is another purpose of this invention to provide such compositions that contain other oxidant biocides in general.
A further purpose is the provision of biocide tablets for the sanitation of bodies of water.
Other purposes and advantages of the invention will appear as the description proceeds.